#include<stdio.h>
// x86架构：地址长度为32位  =>内存最大容量为2^32B = 4GB
// x64架构：地址长度为64位  =>内存最大容量为2^64B = 16000TB
int main()
{
    int a[4] = {2016,2017,2018,2019};
    int *ptr = (int *)(&a + 1);
    int *ptr2 = (int *)((long)a+1);
    printf("%d %d\n",ptr[-1],*ptr2);

    //ptr[-1] = *(ptr - 1)

    return 0;
}